SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '495f3234c63302f0b721d9e72516c242f5206984f36536204d0bdfaa08b69dc4' 
  AND token = 's9Q0BTXqu5LZBKjlb8JoCnKtJGykb5MfRAXMcSQh+rg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}